J. D. Buck was a prominent theosophist, an influential Freemason, as well as a writer on both subjects. In this particular piece from 1897, he writes about the importance of self-discipline and how it's tied in with the concept of power. He writes about controlling one's feelings and conquering one's passions in order to achieve and maintain the ability of self-mastery. He also talks about universal brotherhood, a concept important to theosophists and Freemasons alike.
Public Domain (P)2015 Lamp of Trismegistus